1. Field of the Invention
The present invention relates to a sheet processing apparatus which processes sheets (or paper sheets), a control method of the sheet processing apparatus, and a storage medium which stores therein a program for the control method.
2. Description of the Related Art
In regard to an image forming apparatus, a sheet processing apparatus which performs a post-process such as stapling, saddle stitch bookbinding, saddle stitch binding fold or the like as a function of a finisher has been proposed (Japanese Patent Application Laid-Open No. 2010-33071). Here, in the post-process, the upper limit number of sheets to which the post-process can be performed has been previously determined due to a mechanical limitation of the image forming apparatus.
As described in Japanese Patent Application Laid-Open No. 2010-33071, in a conventional sheet processing apparatus, the upper limit number of sheets for a post-process such as stapling or the like is fixedly determined.
More specifically, in the conventional sheet processing apparatus, it has been set to be able to perform a stapling process up to 60 sheets based on plain paper. However, although it may be possible to perform the stapling process at a time up to 80 sheets if paper having the thickness thinner than that of the plain paper is used, the stapling process could not be performed to 80 thin-paper sheets because such a kind of paper could not be handled. In recent years, kinds of sheets capable of being handled by the sheet processing apparatus have increased.
Incidentally, such a problem as above occurs not only in the stapling process but also in another post-process such as a folding process or the like.